Melt the butter partially, then mix it until it thickens again and it becomes like a cream. Add the sugar and vanilla essence and mix until the sugar melts and the cream becomes frothy. Add the egg and mix well until completely incorporated. Then pour the flour and mix with a spoon.
We put the obtained dough in a posh and we sprinkle small lumps of dough, at a distance from each other.
Bake on medium heat for 10-15 minutes, until the edges begin to brown. The easiest way is to check the "sole" of the cookie, if it has browned I am ready. Remove to a grill and leave to cool.
Serve simple or garnished with melted chocolate. We preferred the simple option.